Hydrazine → 3-phenyl-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To 2-fluorobenzophenone (1.0 g, 5.0 mmol) was added hydrazine (5 mL) and the reaction was heated to reflux for 3 hours. The reaction was then added to water (100 mL) and extracted with ethyl acetate (3×30 mL). The combined organic layers were dried with sodium sulfate (Na2SO4) and concentrated to an oil. The subsequent hydrazine adduct was heated with pyridine (20 mL) to 170° C. for 4 days. Pyridine was then removed under vacuum and the resulting oil taken up in water (100 mL) and extracted with ethyl acetate (3×30 mL). The combined ethyl acetate layers were dried (Na2SO4) and concentrated to give the final compound (650 mg, 67% yield). 1H NMR (CDCl3) δ 10.6 (br s, 1H), 8.04-7.99 (m, 2H), 7.56-7.50 (m, 2H), 7.47-7.33 (m, 2H), 7.29-7.19 (m, 3H); ES-MS (m/z) 195 [M+1]−.

Provenance & Evidence